This invention relates to means for reducing the spread of shots in a weapon system in which the shots are fired from the weapon in a ballistic trajectory from a launching site towards a target and which comprises means for measuring target parameters and means for measuring the muzzle velocity of the shot.
Though it is now possible to more precisely determine the position of a target, and more sophisticated computers are used in the firing control equipment, there are, however, a number of factors which give rise to the spread of shots. As a result, the hit probability is rapidly reduced in proportion to the firing distance. In order to strike target a great number of shots are required, and also a considerable amount of time is required, which as a rule is not available in a duel fight.
For targets located within sight of the launching site, the hit probability can be increased by using guided projectiles or missiles, for instance a missle which is guided towards the target automatically or manually during the entire missile trajectory. Such systems are very complicated and therefore expensive. Specific missile launching devices are required and the target must be observed and followed by the operator.
In order to improve the hit probability and the effective firing range of, for instance, conventional antitank weaspon systems, efforts have recently been directed to terminally corrected projectiles. In such systems the projectiles are fired from conventional guns in a ballistic trajectory towards the target. In the vicinity of the target, a target detector is initiated to provide the required correction of the projectile in order to hit the target.
In order to achieve terminal correction, a target detector is then required which provides an error signal if the projectile is on its way to a point off target, and also a correction member for correcting the trajectory of the projectile in accordance with the error signal. The target detector can consist of, for instance, an IR-detector which, with a scanning lobe, senses the area around the target and, if the target is detected, transmits one or several guidance pulses to the correction member so that the trajectory of the projectile is changed and is directed towards the target.
A terminally corrected projectile of this type is previously known from Swedish Patent No. 76.03926-2, in which the correction member comprises a number of nozzles each connected with a respective detector and being actuable upon receipt of a signal from its respective detector.
Even if such a terminally corrected projectile, is less complicated and expensive compared with a guided missile, the projectile must be provided with rather complicated components such as the target detector and the correction member. Furthermore, a laser beam designator is required for illuminating the target. The reflected laser beam from the laser-illuminated target surface is detected by the target detector and, depending on the location of this reflected laser beam, a correction signal is provided by the detector to correct the ballistic trajectory.